A primary concern for coffee roasters is preserving the freshness of their roasted coffee. An integral tool in achieving this is the degassing valve.
Patented in 1960, the degassing valve is a one-way vent that allows coffee beans to gradually release gases such as carbon dioxide (CO2), without coming into contact with oxygen.
While they may look like simple plastic nozzles, degassing valves are highly valued products, allowing roasted coffee to travel longer distances without being compromised.
However, their addition to sustainable coffee packaging can be problematic as they will often need to be removed before disposal. As such, some roasters may opt for bags without degassing valves, providing their coffee will be consumed shortly after roasting.
Read on to find out more about degassing valves and the alternative options available to roasters.
Why use a degassing valve?
When coffee is roasted, it undergoes dramatic physical changes as its volume increases by up to 80%.
Furthermore, the act of roasting releases gases trapped in the bean, with roughly 78% consisting of carbon dioxide (CO2).
Degassing continues throughout a coffee’s packaging, grinding, and consumption. For example, 26% and 59% of the coffee’s CO2 is released after grinding for coarse, medium, and fine grind sizes respectively.
While the presence of CO2 is often a sign of freshness, it may negatively impact a coffee’s flavour and aroma. For instance, a coffee that has not had enough time to degas may generate bubbles during brewing, leading to uneven extraction.
Degassing needs to be carefully controlled, as too much can render the coffee stale. Too little degassing, however, can impact a coffee’s ability to extract properly and form crema.
Over time, through trial and error, roasters found numerous ways to manage the degassing process.
Past solutions included allowing the coffee to degas before packaging or using rigid packaging that could withstand the pressure of CO2 buildup. Additionally, they tried vacuum sealing coffee in its packaging.
However, each method had its drawbacks. For instance, waiting for the coffee to degas took too long and exposed the beans to oxidation. Alternatively, rigid packaging was expensive and impractical for transportation.
The method of vacuum sealing removed too many of the coffee’s aroma volatiles, which negatively affected its sensory characteristics.
The breakthrough came in the 1960s with the introduction of the degassing valve by Italian packaging manufacturer Goglio.
Virtually unchanged to this day, the degassing valve consists of a rubber diaphragm enclosed within an injected moulded valve. Its inner layer contains a liquid layer that maintains surface tension against the valve’s body.
When the surface tension is reached by the pressure differential, the liquid shifts away and moves the diaphragm. This allows gas to escape while preventing oxygen from entering the package.
The problem with degassing valves
While degassing valves have revolutionised the way coffee is packaged, there are many reasons roasters may not want to use one.
The most obvious one is that it adds to packaging costs. Additionally, some roasters are concerned that valves accelerate the loss of aromatics. They found sealing a bag without a valve may cause it to expand and puff up, but it does not explode.
As a result, these roasters often choose to vacuum seal their coffee instead.
Another concern over degassing valves stems from the confusion over whether they are recyclable.
Often, there is limited information on how degassing valves should be separated and recycled. Much of this confusion is passed down to the consumer, as valve recycling instructions are rarely printed on coffee packaging.
More consumers are becoming aware of the environmental impact of their purchasing decisions. Therefore, a lack of recycling information on coffee packaging may cause them to switch to another brand.
One solution for roasters is to select recyclable degassing valves for their coffee bags. These can be added to packaging quickly and efficiently, and some use up to 90% less plastic.
Alternatively, some degassing valves are made from bioplastics such as polylactic acid, making them more cost effective for roasters and better for the planet.
A key point when using these options is to communicate the valve’s disposal instructions on coffee packaging, such as how it can be removed for recycling.
Does all coffee packaging need degassing valves?
A roaster’s decision to use a degassing valve can hinge on many factors. These include the roast profile and whether they are selling whole beans or ground coffee.
For example, darker roasts tend to degas more quickly than light roasts, despite having a higher buildup of gases. This is because the structure of the beans becomes more porous the longer they spend in the roaster.
A key point is for roasters to understand their customers’ consumption preferences. This will help determine the average size of the packaged coffee, as well as the order volumes required.
When the coffee is sold in smaller volumes, it often does not have enough time to cause problems to packaging without a degassing valve. This is because customers will make their way through the coffee quicker than they would for larger volumes, such as 1kg bags.
In such instances, roasters may decide to offer customers smaller volumes of coffee.
For roasters who choose not to use degassing valves, there are ways to avoid the risk of oxidation. For example, some roasters use nitrogen flushing, while others include oxygen and CO2 absorbing sachets in their packaging.
Alternatively, roasters can make sure the packaging’s sealing mechanism is as airtight as possible. A zip seal may be more effective at preventing oxygen from entering coffee bags than the tin tie method, for example.
Degassing valves are one of the many tools available to roasters to ensure their coffee arrives at customers in pristine condition.
Whether roasters choose to use a degassing valve or not, partnering with a packaging expert can help preserve the coffee’s characteristics, and ensure customers come back for more.
At MTPak Coffee, we offer fully recyclable, BPA-free degassing valves that can be recycled along with the rest of the coffee packaging. These valves usually consist of five pieces: a cap, an elastic disc, a viscous layer, a polyethylene plate, and a paper filter.
Not only do they contribute to creating a user-friendly product for consumers, they also reduce the negative impact of coffee packaging on the environment.
Furthermore, we offer ziplocks, along with velcro zippers, tin ties and tear notches, providing you with a range of options for keeping your coffee fresh.
Velcro zippers offer audible confirmation of secure closure, while tear notches reassure your customers that your packaging is tamper-free and fresh as possible. Tin ties may work best with our flat bottom pouches to retain structure of the packaging.